## From PSS vol. 18

In France, idealist philosophy seized upon the vacillations of Machist physics no less decisively. We have already seen how the neocriticists received Mach's *Mechanics*, immediately noting the idealist character of the foundations of Mach's philosophy. The French Machist Poincaré (Henri) had even greater success in this respect. The most reactionary idealist philosophy, with decidedly fideistic conclusions, immediately seized upon his theory. The representative of this philosophy, Le Roy, reasoned as follows: the truths of science are conventional signs, symbols; you have abandoned absurd, "metaphysical" pretensions to knowledge of objective reality; then be logical and agree with us that science has only practical significance for one sphere of human activity, while religion has no less actual significance than science for another sphere of activity; symbolic, Machist science has no right to deny theology. A. Poincaré was ashamed of these conclusions and in his book *The Value of Science* specifically attacked them. But observe what epistemological position he was forced to adopt in order to free himself from allies of the Le Roy type. "Mr. Le Roy," writes Poincaré, "declares reason hopelessly powerless only in order to make more room for other sources of knowledge, for heart, feeling, instinct, faith" (214–215). "I do not go all the way": scientific laws are conventions, symbols, but "if scientific 'recipes' have value as rules for action, it is because, generally speaking, they are successful for us, as we know. To know this—means already to know something, and if that is so—what right have you to tell us that we can know nothing?" (219).

A. Poincaré appeals to the criterion of practice. But he only displaces this question, rather than resolving it, for this criterion can be interpreted in both a subjective and an objective sense. Le Roy likewise recognizes this criterion for science and industry; he only denies that this criterion proves objective truth, and such denial is sufficient for him to recognize the subjective truth of religion alongside the subjective (non-existent apart from humanity) truth of science. A. Poincaré sees that one cannot confine oneself to an appeal to practice against Le Roy, and he proceeds to the question of the objectivity of science. "What is the criterion of the objectivity of science? The same as the criterion of our faith in external objects. These objects are real insofar as the sensations which they produce in us (qu'ils nous font éprouver) appear to us to be connected, I know not by what indestructible cement, and not by chance of the day" (269–270).

That the author of such reasoning can be a major physicist is admissible. But it is entirely indisputable that only Voroshilovs-Yushkevichs can take him seriously as a philosopher. We declared materialism destroyed by a "theory" which at the first onslaught of fideism takes refuge under the wing of materialism! For this is the purest materialism if you hold that sensations are produced in us by real objects and that "faith" in the objectivity of science is the same as "faith" in the objective existence of external objects.

"...One can say, for example, that ether has no less reality than any external body" (270).

What a commotion the Machists would raise if a materialist had said this! How many toothless witticisms there would be about "ethereal materialism" and such! But the founder of the newest empirio-symbolism a few pages later proclaims: "All that is thought is pure nothing; for we can think nothing except thought" (276). You are mistaken, Mr. Poincaré: your works prove that there are people who can think only nonsense. To this class belongs the notorious muddle-head Georges Sorel, who asserts that "the first two parts" of Poincaré's book on the value of science "are written in the spirit of Le Roy" and that therefore both these philosophers can be "reconciled" on the following: the attempt to establish identity between science and the external world is an illusion; there is no need to raise the question of whether science can know nature; it suffices that science corresponds with mechanisms we create (Georges Sorel: *"Les préoccupations métaphysiques des physiciens modernes"*, P., 1907, p. 77, 80, 81[184]).

But while Poincaré's "philosophy" need only be noted and passed by, we must dwell in detail on A. Rey's work. We have already indicated that the two main tendencies in contemporary physics, which Rey calls "conceptualist" and "neomechanist," reduce to the distinction between idealist and materialist epistemology. We must now see how the positivist Rey solves a task diametrically opposed to that of the spiritualist J. Ward, the idealists G. Cohen and E. Hartmann—namely: not to adopt the philosophical errors of the new physics, its inclination toward idealism, but to correct these errors, to prove the illegitimacy of idealist (and fideistic) conclusions from the new physics.

Throughout A. Rey's work runs like a scarlet thread the recognition of the fact that fideism (p. II, 17, 220, 362, etc.) and "philosophical idealism" (200), skepticism regarding the rights of Reason and the rights of science (210, 220), subjectivism (311), and so forth, have seized upon the new theory of physics of the "conceptualists" (Machists). And for this reason A. Rey rightly makes the center of his work the analysis of "the opinions of physicists regarding the objective value of physics" (3).

What are the results of this analysis?

Let us take the basic concept—the concept of experience. Rey assures us that Mach's subjectivist interpretation (we take him for simplicity and brevity as the representative of the school Rey calls conceptualist) is a sheer misunderstanding. True, among the "principal new features of the philosophy of the end of the nineteenth century" belongs the fact that "empiricism, ever more refined, ever richer in nuance, leads to fideism, to the recognition of the primacy of faith—empiricism which once was the great weapon in the struggle of skepticism against the assertions of metaphysics. Did this not occur because, in essence, through imperceptible nuances, gradually, the real meaning of the word 'experience' was distorted? In fact, experience, if taken in its conditions of existence, in that experimental science which determines it and refines it—experience leads us to necessity and to truth" (398). It is undoubtedly true that all Machism, in the broad sense of the word, is nothing other than a distortion through imperceptible nuances of the real meaning of the word "experience"! But how does Rey correct this distortion, blaming only the fideists for it and not Mach himself? Listen: "Experience, according to the ordinary definition, is knowledge of an object. In physical science this definition is more appropriate than anywhere else… Experience is that over which our mind has no power, which cannot be changed by our desires, our will—that which is given, which we do not create. Experience is the object before (en face du) the subject" (314).

Here you have a specimen of Rey's defense of Machism! How profoundly foresighted Engels was in characterizing the newest type of supporters of philosophical agnosticism and phenomenalism with the epithet: "shamefaced materialists." The positivist and ardent phenomenalist Rey is an excellent example of this type. If experience is "knowledge of an object," if "experience is the object before the subject," if experience consists in the fact that "something external (quelque chose du dehors) exists and exists necessarily" (se pose et en se posant s'impose, p. 324)—then this obviously reduces to materialism! Rey's phenomenalism, his most assiduous insistence that there is nothing but sensations, that the objective is the universally valid, and so on and so forth—this is all a fig leaf, an empty verbal covering for materialism, once we are told:

"That is objective which is given us from without, imposed (imposé) by experience; that which we do not produce, which is produced independently of us and which in some degree produces us" (320). Rey defends "conceptualism" by destroying conceptualism! The refutation of idealist conclusions from Machism is achieved only by interpreting Machism in the sense of shamefaced materialism. Having himself acknowledged the distinction between two tendencies in contemporary physics, Rey labors mightily to erase all distinctions in favor of the materialist tendency. For example, regarding the school of neomechanism Rey says that it permits "not the slightest doubt, not the slightest uncertainty" on the question of the objectivity of physics (237): "here (i.e., on the ground of the teachings of this school) you are far from all those detours through which you were forced to go from the standpoint of other theories of physics in order to arrive at the assertion of this objectivity."

It is precisely these "detours" of Machism that Rey conceals, throws a veil over throughout his presentation. The basic feature of materialism is precisely that it proceeds from the objectivity of science, from the recognition of objective reality as reflected by science, whereas idealism needs "detours" in order to somehow "derive" objectivity from spirit, consciousness, from the "psychic." "The neomechanist (i.e., dominant) school in physics," writes Rey, "believes in the reality of physical theory in the same sense in which humanity believes in the reality of the external world" (p. 234, § 22: thesis). For this school "theory wants to be a tracing (le décalque) from the object" (235).

Correct. And this basic feature of the "neomechanist" school is nothing other than the foundation of materialist epistemology. No renunciations by Rey of the materialists, no assurances of his that the neomechanists are also, in essence, phenomenalists and so forth, can weaken this fundamental fact. The essence of the distinction between neomechanists (materialists more or less shamefaced) and Machists consists precisely in the fact that the latter retreat from such a theory of knowledge and, in retreating from it, inevitably stumble into fideism.

Take Rey's relationship to Mach's doctrine on causality and the necessity of nature. Only at first glance, assures Rey, does Mach "approach skepticism" (76) and "subjectivism" (76); this "ambiguity" (équivoque, p. 115) dissolves if one takes Mach's doctrine as a whole. And Rey takes it as a whole, brings forth a series of quotations both from *The Science of Heat* and from the *Analysis of Sensations*, specifically dwells on the chapter on causality in the first of the mentioned works—but... but carefully avoids citing the decisive passage, Mach's assertion that there is no physical necessity, only logical! To this one can only say that this is not an interpretation but a touching up of Mach, that this is an erasing of distinctions between "neomechanism" and Machism. Rey's conclusion: "Mach continues the analysis and accepts the conclusions of Hume, Mill, and all phenomenalists, according to whose view causality contains nothing substantial in itself and is only a habit of thought. Mach accepts the fundamental thesis of phenomenalism, relative to which the doctrine of causality is a simple consequence, namely: that nothing exists except sensations. But Mach adds in a purely objectivist direction: science, investigating sensations, finds in them constant and general elements which, being abstracted from sensations, have the same reality as they do, for they are drawn from sensations through sensuous observation. And these constant and general elements, such as: energy and its transformations, form the basis of the systematization of physics" (117).

It turns out that Mach accepts Hume's subjective theory of causality and interprets it in an objectivist sense! Rey equivocates, defending Mach by appeals to his inconsistency and drawing out the notion that in the "real" interpretation of experience, this experience leads to "necessity." And experience is that which is given from without, and if the necessity of nature, its laws, are likewise given from without to man, from objectively-real nature, then of course all difference between Machism and materialism vanishes. Rey defends Machism against "neomechanism" by capitulating all along the line to the latter, insisting on the little word phenomenalism rather than the substance of this tendency.

Poincaré, for example, entirely in the spirit of Mach derives the laws of nature—even to the point that space has three dimensions—from "convenience." But this does not at all mean "arbitrary," Rey hastens to "correct." No, "convenient" expresses here {{adaptation to the object" (Rey's emphasis, p. 196). Nothing to say about it—a splendid demarcation of the two schools and "refutation" of materialism... "If Poincaré's theory is separated by a logically impassable chasm from the ontological interpretation of the mechanist school" (i.e., from that school's recognition that theory is a tracing from the object)... "if Poincaré's theory is capable of serving as a support for philosophical idealism, then at least on the ground of science it agrees very well with the general development of ideas of classical physics, with the tendency to regard physics as objective knowledge, as objective as experience itself, i.e., as the sensations from which experience proceeds" (200).

On the one hand, one cannot but confess; on the other hand, one must acknowledge. On the one hand, an impassable chasm separates Poincaré from neomechanism, although Poincaré stands in the middle between Mach's "conceptualism" and neomechanism, while Mach supposedly is not separated from neomechanism by any chasm at all. On the other hand, Poincaré is entirely consistent with classical physics, which, according to Rey's own words, stands wholly on the standpoint of "mechanism." On the one hand, Poincaré's theory is capable of serving as a support for philosophical idealism; on the other hand, it is compatible with an objective interpretation of the word "experience." On the one hand, these wicked fideists have distorted the meaning of the word "experience" through imperceptible deviations, retreating from the correct view that "experience is an object"; on the other hand, the objectivity of experience means only that experience is sensations—with which Berkeley and Fichte are in perfect agreement!

Rey became entangled because he set himself an insoluble task: to "reconcile" the opposition between the materialist and idealist schools in the new physics. He attempts to weaken the materialism of the neomechanist school by bringing the views of physicists who consider their theory a tracing from the object under phenomenalism[185]. And he attempts to weaken the idealism of the conceptualist school by cutting off the most decisive statements of its adherents and interpreting the rest in the sense of shamefaced materialism. To what degree fictive and strained is Rey's renunciation of materialism in this process is shown, for example, by his assessment of the theoretical significance of the differential equations of Maxwell and Hertz. For the Machists, the fact that these physicists limit their theory to a system of equations is a refutation of materialism: equations—and that is all, no matter, no objective reality, only symbols. Boltzmann refutes this view, understanding that he is refuting phenomenological physics. Rey refutes it, thinking to defend phenomenalism! "One cannot refuse," he says, "to classify Maxwell and Hertz among the 'mechanists' on the ground that they limited themselves to equations similar to the differential equations in Lagrange's dynamics. This does not mean that, in the opinion of Maxwell and Hertz, we will not be able to construct a mechanical theory of electricity on real elements. On the contrary, the possibility of this is proved by the fact that electric phenomena are represented by a theory whose form is identical with the general form of classical mechanics" (253)... The indeterminacy in the present solution of the problem "will diminish as the nature of those quantitative units, i.e., elements which enter into the equations, becomes more clearly delineated." For Rey, the incomplete investigation of one or another form of material motion is not grounds for denying the materiality of motion. "The homogeneity of matter" (262)—not as a postulate but as a result of experience and the development of science, "the homogeneity of the object of physics"—this is what constitutes the condition for the applicability of measurements and mathematical calculations.

Here is Rey's assessment of the criterion of practice in the theory of knowledge: "In contradiction to the premises of skepticism we have the right to say that the practical value of science flows from its theoretical value" (368)... Regarding the fact that these skeptical premises have been quite unambiguously adopted by Mach, Poincaré, and their entire school, Rey prefers to remain silent... "And both values are two inseparable and strictly parallel aspects of its objective value. To say that a given law of nature has practical value... is, in essence, to say that this law of nature has objective significance... To affect an object presupposes a change in the object, a reaction of the object corresponding to our expectations or forecasts on the basis of which we undertook this action. Consequently, these expectations or forecasts contain in themselves elements controlled by the object and our action... In these various theories there is, consequently, a part of the objective" (368). This is a thoroughly materialist and only materialist theory of knowledge, for other standpoints, and Machism in particular, deny the objective, i.e., independent of man and humanity, significance of the criterion of practice.

Conclusion: Rey approached the question from a completely different side than Ward, Cohen and Co., yet the results turned out to be the same—the recognition of materialist and idealist tendencies as the basis of the division between the two main schools in contemporary physics.